Electron-discharge device



E 1 569 630 T. R. GRIFFITH E ELECTRON DISCHARGE DEVICE Filed Dec. Q 12, 1923 Men/0r. Mamas/7? 6r/7/77/2 E Patented Jan. 12, 1926.

UNITED STATES: PATENT OFFICE.

rnomas a. GRIFFITH, or novna, NEW

masav, assrenon r wnsrmm amoral:

COMPANY, INCORPORATED, OF NEW' YOBK, N. Y., CORPORATION 01' NEW YORK.

ELECTRON-DISCHARGE DEVICE.

Application filed December 12, 1923. Serial No. 680,169. I

To all whom it may concern:

Be it known that I, THoMAs R. GRIFFITH,

a citizen of the United States of America, residing at Dover, inthe county'of Morr s, State of New Jersey, have invented certain new and useful Improvements in Electron- Discharge Devices, of which the follow ng is a full, clear, concise, and exact description.

This invention relates to electron discharge devices and more particularly to high power vacuum tubes, its object be ng to improve the electrode supporting structure in this device. w

In high'power vacuum tubes of certain types, the cathode and grid electrodes are arranged between two blocks of insulating material. The insulating blocks are generally spaced apart by means of metallic rods, which are usually attached to the insulating blocks b nuts on both sides of the blocks or by 'swe ging or enlargin the ends of the metallic rods. These met ods ro duce strains in the insulatin block -w ich are liable to cause fracture o the block.

According to this invention, each block of insulating material is provided with an aperture for the respective metallic rod, and in addition, one side. of each insulating block is provided with an elongated slot or groove, adjacent the aperture. The metallic rod is inserted in the apertures in the insulating blocks and the rod has a .folded portion at right angles to the axis of the rod which is seated in the elongated slot in the insulating blocks. The space is then filled with cement, to securely hold the rod in the insulating blocks. ThlS arrangement prevents the rod becoming loose in the in-v sulating blocks. It eliminates entirely the undesirable breakage of the insulating block due to the strain occasioned by the pressure required to provide a tight connection between the metal rod and the insulating blocks. The cement allows the rod to take its natural shape in the aperture, without tension, and when set, provides an integral Referring to the drawings: Fig. 1 illustrates an electron discharge device embodying this invention.

Fig. 2 isa plan view of the apertured insulating block. 1

Fig. 3 is a view in cross section of the joint.

A metallic collar 15 encircles the neck 14,

held thereon. The me- .centre of the block ,device is illustrated comprising a cylindrical metal anode 10, with a metallic cap 11, hermetically closing one end. A glass portion 12, with a reentrant neck 14 is joined to the metal anode between the metal anode 10 and glass p0rtion 12, may be made in accordance with G. Houskeeper, U. S. Patent 1,294,466.

and is frictionally' tallic collar 15 is provided with integral .lugs 16, throughwhich-the rods 17 aresupported in the usual manner... The rods 17 are bent inwardly to register with the aperinsulating block 19 is rovided with apertures 20, through whic the filament leads 21 extend. The grid lead 23 extends through aperture 22 in the insulating block 19 and is enclosed in the tubular member 24 which is hermetically sealed at 25. The sealing arrangement is not essential to an understanding of this invention, since this feature is described in W. G. Houskeeper U. S. Patent 1,293,441.

The insulating block 19 is provided with elongated slots or grooves 27, adjacent one side of the block and rojecting toward the ,or groove 27.

The slot 27 is thereafter filled with an aluminum oxide cement 28, which is commercially known as alundum.

This aluminum oxide cement consists of electrically fused alumina with a ceramic. bond and can be obtained in granular or powder form. The dry cement is mixed with the proper amount mass of therequired consistency for working. This cement flows the crevices aroundtherod 17 in the slot 27. and aperture 26.

The assembly is then placed in an oven and heated to a temperature of approxi+ mately 1,000'

G At this temperature the cement vltrifiesand forms a solid mass with p This construction PIOYIdBS a highly eflicient connection bethe insulating blocks.

at 13 The joint 13,

tures 26 in theinsulating block 19. The

rom the cooperating of water to form. a m

very freely andfills tween the metallic member. and the insulatside of said block, a uploortingro nd athigh ternpenatnres it tl ro saidbloek, said rod havin a horito racture. Althoti fltliisinzonta foltl'ed.portion seated in saiddepres- 11 described with referencedusion, and an electrically fused alumina oxidecernent, it is entirely b: der enclosing the folded portion of the QP hfl i I l i l kthe" ram discharge device comprisn hat oth r s 11 'd""'qualities i n electron tenacity and resistance to g .,,an,,,apertured insulating block, said used with equal results.

vtract re 9 n The" ntlon- 1s block" having radial grooves on one side only to be limited within; the scope oiwtheg; tlgeneof, ,supportingrods in said block havappended claims. 9

"Whatiisiolaimed is;

ing integrally fol d portions, said folded In an electr4on disc 1 portions being positioned in saidgrooves, and" ani alumlnum oxide binder 1n said ap tuiedi mbe1, fa' gro v adjae grooves! e a aperture, a support ng 1o" havin .551.111 an electron discharge device, an

apertured insulating block, a groove: in said block onnectingwith said aperture, a mate a inserted in said apertured insulating block, said rod having a folded portion seated in said groove, and a binder enclosing saidfolded portion in said groove, said; binder being capable of withstanding 't mpe tatures of the order of 100030,;

witness whereof, I hereunto subscribe jection =pol i'o e yi-ina a d groove .c'ejmenta enl'fosing said' projection, supportingl'rod ail! said gro vet,

2.; Amizlectr n di h rg ing anapertured insulatin bloc oove -bnqonesside of said lock, serted in said block, a port ongof W being of friregulari formation; and" {seated said gno W and afusedia m "founding said inisaidiins 1 ti fTiioMAs n; GRIFlI ITH."

my nafne th's 5th day of December A. D., 

